My Dad's Ryan weedeater's bump head won't feed out line anymore while running it and tapping it on the ground. You have to stop the engine & manual push in the bump head all the way, rotate the spool, then you have to lift off the bump head a little bit to a certain point before the spool will rotate fully. Is it possible for that bump head setup to get out of whack? Or does the entire bump head/spool need to be replaced once it acts up? Where can parts for it be found? Is Ryan still around under a different name? Thanks in advance.